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    <title>ShellCheck: SC2037 – To assign the output of a command, use `var=$(cmd)` .</title>
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    <h1>SC2037 – ShellCheck Wiki</h1>
    <a href="https://github.com/koalaman/shellcheck/wiki/SC2037">See this page on GitHub</a>
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    <h2 id="to-assign-the-output-of-a-command-use-varcmd-">To assign the
output of a command, use <code>var=$(cmd)</code> .</h2>
<h3 id="problematic-code">Problematic code:</h3>
<div class="sourceCode" id="cb1"><pre class="sourceCode sh"><code class="sourceCode bash"><span id="cb1-1"><a href="SC2037.html#cb1-1" aria-hidden="true" tabindex="-1"></a><span class="va">var</span><span class="op">=</span>grep <span class="ex">-c</span> pattern file</span></code></pre></div>
<h3 id="correct-code">Correct code:</h3>
<div class="sourceCode" id="cb2"><pre class="sourceCode sh"><code class="sourceCode bash"><span id="cb2-1"><a href="SC2037.html#cb2-1" aria-hidden="true" tabindex="-1"></a><span class="va">var</span><span class="op">=</span><span class="va">$(</span><span class="fu">grep</span> <span class="at">-c</span> pattern file<span class="va">)</span></span></code></pre></div>
<h3 id="rationale">Rationale:</h3>
<p>To assign the output of a command to a variable, use
<code>$(command substitution)</code>. Just typing a command after the
<code>=</code> sign does not work.</p>
<h3 id="exceptions">Exceptions:</h3>
<p>None.</p>
<p>This warning triggers generally for <code>var=value -flag</code> and
<code>var=value *glob*</code>. See related warning <a
href="SC2209.html">SC2209</a> which matches
<code>var=commonCommand</code>.</p>
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    <p style='font-size: 80%'><a href="../index.html">ShellCheck</a> is a static analysis tool for shell scripts. This page is part of its documentation.</p>
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